Photovoltaic device

ABSTRACT

The present invention is premised upon an improved photovoltaic device (“PV device”), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

CLAIM OF PRIORITY

The present application claims the benefit of the filing date of U.S.Provisional Application No. 61/424,325 filed on Dec. 17, 2010 thecontents of which are hereby incorporated by reference in theirentirety.

This invention was made with U.S. Government support under contractDE-FC36-07G017054 awarded by the Department of Energy. The U.S.Government has certain rights in this invention.

FIELD OF THE INVENTION

The present invention relates to an improved photovoltaic device (“PVD”or “PV device”), more particularly to an improved photovoltaic devicewith a multilayered photovoltaic cell assembly in the form of a paneland a body portion joined at an interface region including at least oneinterconnecting member, at least one interconnecting structural member,relieving feature, unique component geometry, or any combinationthereof.

BACKGROUND

Efforts to improve PV devices, particularly those devices that areintegrated into building structures (e.g. roofing shingles or exteriorwall coverings), to be used successfully, should satisfy a number ofcriteria. The PV device should be durable (e.g. long lasting, sealedagainst moisture and other environmental conditions) and protected frommechanical abuse over the desired lifetime of the product, preferably atleast 10 years, more preferably at least 25 years. The device should beeasily installed (e.g. installation similar to conventional roofingshingles or exterior wall coverings) or replaced (e.g. if damaged). Itmay be desirable to choose materials and components, along with designfeatures that aid in meeting the desired durability requirements such asbeing free of deformations that would impair performance (for example aspublished in United Laboratories UL 1703 Standard—ISBN 0-7629-0760-6 andor Temperature Cycling Test pursuant to IEC16646).

To make this full package desirable to the consumer, and to gain wideacceptance in the marketplace, the system should be inexpensive to buildand install. This may help facilitate lower generated cost of energy,making PV technology more competitive relative to other means ofgenerating electricity.

Existing art systems for PV devices may allow for the device to bedirectly mounted to the building structure or they may fasten thedevices to battens, channels or “rails” (“stand-offs)) above thebuilding exterior (e.g. roof deck or exterior cladding). These systemsmay be complicated, typically do not install like conventional claddingmaterials (e.g. roofing shingles or siding) and, as a consequence, maybe expensive to install. Also, they may not be visually appealing asthey do not look like conventional building materials. “Stand-offs” tomount PV device every 2-4 feet may be required. Thus, installation costcan be as much or more as the cost of the article. They also may sufferfrom issues related to environmental conditions such as warping, fadingand degradation of its physical properties.

Among the literature that can pertain to this technology include thefollowing patent documents: US20080190047(A1); U.S. Pat. Nos. 4,321,416;5,575,861; 5,437,735; 5,990,414; 6,840,799; EP1744372; U.S. Pat. Nos.6,875,914; 5,590,495; 5,986,203; US2008/0115822; EP1923920; U.S. Pat.No. 7,365,266; US20070295393 A1; US20070295392 A1; WO 2008/139102; WO2009/137348; WO 2009/137347; WO 2009/137352; WO 2009/137353; and U.S.Provisional 61/233,527, all incorporated herein by reference for allpurposes.

SUMMARY OF THE INVENTION

The present invention is directed to a PV device that addresses at leastone or more of the issues described in the above paragraphs.

Accordingly, pursuant to one aspect of the present invention, there iscontemplated a photovoltaic device that includes at least: athree-dimensional multi-layered photovoltaic cell assembly in the formof a panel with at least a top surface, a bottom surface, and aperipheral edge, further including a barrier layer; a body portion,wherein the body portion is at least partially surrounding a portion ofthe top surface and peripheral edge of the three-dimensionalmulti-layered photovoltaic cell assembly; and at least one relievingfeature disposed in the panel or in the body portion adapted to allowelastic deformation of the photovoltaic device over a temperature range.

The invention may be further characterized by one or any combination ofthe features described herein, such as the three-dimensionalmulti-layered photovoltaic cell assembly includes at least oneelectrical connector assembly with a connector housing, the housinghaving an outer surface; the three-dimensional multi-layeredphotovoltaic cell assembly includes two electrical connector assembliesdisposed on opposite sides of the assembly; the plurality of relievingfeatures are disposed in the body portion at least partially between thebarrier layer and the housing of the two electrical connectorassemblies; the relieving features are disposed within 15.0 mm of thebarrier layer of the three-dimensional multi-layered photovoltaic cellassembly along at least 50 percent of a top peripheral edge; therelieving features are disposed within 5.0 mm of a top peripheral edgeof the connector housing; the relieving feature comprises a barrierlayer divided in at least two pieces with at least a relievingelastomeric barrier between each piece; the relieving feature comprisesat least a partial thinning of the body portion between a corner of theconnector housing and a rounded barrier perimeter corner; the relievingfeature comprises a localized thinning of the body portion, wherein thelocalized thinning has a depth of at least 50 percent that of a depth ofthe three-dimensional multi-layered photovoltaic cell assembly; therelieving feature includes an elastomeric filling material; the barrierlayer is comprised of a glass with a thickness of 1.0 to 5.0 mm; atleast one interconnecting structural member; at least the body portionis comprised of: a body material with a body CLTE, the body portion witha body lower surface portion, body upper surface portion and a body sidesurface portion spanning between the upper and lower surface portionsand forming a body peripheral edge, wherein at least a portion of thebody portion abuts to a segment of the barrier layer peripheral edge atan interface region; (A) the segment of the barrier layer peripheraledge that abuts the portion of the body portion has rounded barrierperimeter corners within the segment and/or (B) the device furtherincludes at least one component of the electrical connector assembly atleast partially embedded in the body side surface portion and theconnector assembly component includes a connector assembly lower surfaceportion, a connector assembly upper surface portion and a connectorassembly side surface portion spanning between the upper and lowersurface portions which forms a connector assembly peripheral edge,wherein the connector assembly peripheral edge that is closest to theinterface region has at least one rounded connector corner, and theconnector assembly is in electrical communication with the photovoltaiccell layer; the multilayered photovoltaic cell assembly is comprised of:at least a barrier layer with a barrier CLTE and a photovoltaic celllayer disposed inboard of a barrier layer peripheral edge, the barrierlayer including a barrier lower surface portion, a barrier upper surfaceportion and a barrier side surface portion spanning between the upperand lower surface portions with a barrier profile between the upper andlower surface portions and a barrier perimeter spanning about thebarrier layer which forms the barrier layer peripheral edge; the bodyportion comprised of: a body material with a body CLTE, the body portionwith a body lower surface portion, body upper surface portion and a bodyside surface portion spanning between the upper and lower surfaceportions and forming a body peripheral edge, wherein at least a portionof the body portion abuts to a segment of the barrier layer peripheraledge at an interface region; the body portion includes a bending regionthat has a thickness (“TBR”) of about 2.5 mm to 4.0 mm, further whereinthe bending region that has a starting point away from the interfaceregion by a distance defined by greater than or equal to a ConstantX′*(body CLTE/barrier CLTE)+a Constant C′, wherein X′ ranges from 1.0 to5.0 and C′ ranges from 1.0 to 5.0; an intermediate layer comprised of alayer material and including a layer elastic modulus value, a layerultimate elongation value, a layer coefficient of thermal expansionvalue and a layer strength value, wherein the intermediate layer is atleast partially disposed between the three-dimensional multi-layeredphotovoltaic cell assembly and the body portion assembly.

It should be appreciated that the above referenced aspects and examplesare non-limiting, as others exist within the present invention, as shownand described herein.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an illustrative PV device according to thepresent invention.

FIG. 2A is a perspective and exploded view of an illustrative PV deviceaccording to the present invention.

FIG. 2B is a perspective and exploded view of another illustrative PVdevice according to the present invention.

FIG. 3 is a plan view of an illustrative connector housing according tothe present invention.

FIG. 4A is a partial plan view of an illustrative PV device showing anexemplary position of an interconnecting member.

FIG. 4B is a sectional view of FIG. 4A.

FIG. 5A is a partial plan view of an illustrative PV device showinganother exemplary position of an interconnecting member.

FIG. 5B is a sectional view of FIG. 5A.

FIG. 6A is a partial plan view of an illustrative PV device showing yetanother exemplary position of an interconnecting member.

FIG. 6B is an exemplary sectional view of FIG. 6A.

FIG. 6C is another exemplary sectional view of FIG. 6A.

FIG. 7A is a partial plan view of an illustrative PV device showing yetanother exemplary position of an interconnecting member.

FIG. 7B is an exemplary sectional view of FIG. 7A.

FIG. 7C is another exemplary sectional view of FIG. 7A.

FIG. 8 is a plan view of an illustrative PV device showing an exemplaryposition of an interconnecting structural member.

FIG. 9A is a plan view of an illustrative PV device showing anotherexemplary position of an interconnecting structural member.

FIG. 9B is a sectional view of 9A through the connector and showing theinterface to the layer 122.

FIG. 10 is a partial plan view of an illustrative PV device showinganother exemplary position of an interconnecting structural member.

FIGS. 11A-F are sectional views of exemplary relief channels (relievingfeatures) according to the present invention.

FIG. 12 is a plan view of an illustrative PV device showing an exemplaryposition of a relieving feature.

FIG. 13 is a plan view of an illustrative PV device showing otherexemplary positions of relieving features.

FIG. 14 is a plan view of an illustrative PV device showing an exemplaryrelieving feature in layer 122.

FIG. 15 is a plan view of an illustrative PV device showing otherexemplary positions of relieving features.

FIG. 16 is a plan view of an illustrative PV device showing otherexemplary positions of relieving features.

FIG. 17 is a perspective view of an illustrative barrier layer accordingto the present invention.

FIG. 18 is a plan view of FIG. 17.

FIG. 19 is a plan view of another illustrative PV device according tothe present invention.

FIG. 20 is a plan view of another illustrative PV device according tothe present invention.

FIG. 21 is a side view of several PV devices on a building structure.

FIG. 22 is a close sectional view of an illustrative bending regionaccording to the present invention.

FIG. 23 is a close sectional view of another illustrative bending regionaccording to the present invention.

FIG. 24 is a side view showing an illustrative desirable cant.

FIG. 25 is a side view showing an illustrative un-desirable cant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to an improved photovoltaic device 10(hereafter “PV device”), as illustrated in FIG. 1, can be describedgenerally as an assembly of a number of components and componentassemblies that functions to provide electrical energy when subjected tosolar radiation (e.g. sunlight). Of particular interest and the mainfocus of the present disclosure is an improved PV device 10 thatincludes at least a multilayered photovoltaic cell assembly 100(hereafter “MPCA”) joined to a body portion 200. In a preferredembodiment, the PV device is formed by taking the MPCA (and potentiallyother components and assemblies such as connector components) andforming (e.g. via injection molding) the body portion about at leastportions the MPCA. It is contemplated that the relationships (e.g. atleast the geometric properties and the material properties) between thecomponents and component assemblies are surprisingly important insolving one or more of the issues discussed in the background sectionabove. Of particular interest in this invention is where the PV device10 is utilized for what is commonly known as Building-IntegratedPhotovoltaics, or BIPV. Each of the components and component assembliesand their relationships are disclosed in greater detail and specificityin the following paragraphs.

Multilayered Photovoltaic Cell Assembly (MPCA) 100

It is contemplated that the MPCA 100 may be a compilation of numerouslayers and components/assemblies, for example as disclosed in currentlypending International patent application No. PCT/US09/042,496,incorporated herein by reference. The MPCA contains at least a barrierlayer 122 and a photovoltaic cell layer 110 (generally located inboardof the peripheral edge of the barrier layer 122). It is contemplatedthat the MPCA 100 may also contain other layers, such as encapsulantlayers and other protective layers. Illustrative examples are shown inthe figures and are discussed below. Exploded views of exemplary MPCAs100 are shown in FIGS. 2A and 2B. It is contemplated that the overallMPCA 100 thickness M_(T) may be about 1 to 12 mm, preferably about 2 to9 mm, and most preferably less than about 9.0 mm.

Functionally, these encapsulant layers and other protective layers mayinclude a number of distinct layers that each serve to protect and/orconnect the MCPA 100 together. Each preferred layer is described infurther detail below, moving from the “top” (e.g. the layer most exposedto the elements) to the “bottom” (e.g. the layer most closely contactingthe building or structure). In general each preferred layer or sheet maybe a single layer or may itself comprise sub layers.

Barrier Layer 122

The barrier layer 122 may function as an environmental shield for theMPCA 100 generally, and more particularly as an environmental shield forat least a portion of the photovoltaic cell layer 110. The barrier layer122 is preferably constructed of a transparent or translucent materialthat allows light energy to pass through to the photoactive portion ofthe photovoltaic cell layer 110. This material may be flexible (e.g. athin polymeric film, a multi-layer film, glass, or glass composite) orbe rigid (e.g. a thick glass or Plexiglas such as polycarbonate). Thematerial may also be characterized by being resistant tomoisture/particle penetration or build up. The barrier layer 122 mayalso function to filter certain wavelengths of light such thatunpreferred wavelengths may not reach the photovoltaic cells. In apreferred embodiment, the barrier layer 122 material will also range inthickness from about 0.05 mm to 10.0 mm, more preferably from about 0.1mm to 4.0 mm, and most preferably from 2.5 mm to 3.5 mm. Other physicalcharacteristics, at least in the case of a film, may include: a tensilestrength of greater than 20 MPa (as measured by JIS K7127); tensileelongation of 1% or greater (as measured by JIS K7127); and/or a waterabsorption (23° C., 24 hours) of 0.05% or less (as measured per ASTMD570); and/or a coefficient of linear expansion (“CLTE”) of about 5×10-6mm/mm° C. to 100×10-6 mm/mm° C., more preferably of about 10×10-6 mm/mm°C. to 80×10-6 mm/mm° C., and most preferably from about 20×10-6 mm/mm°C. to 50×10-6 mm/mm° C. Other physical characteristics, at least in thecase of a thick glass, may include: a coefficient of linear expansion(“CLTE”) of about 5×10-6 mm/mm° C. to about 140×10-6 mm/mm° C.,preferably of about 7×10-6 mm/mm° C. to about 50×10-6 mm/mm° C., morepreferably from about 8×10-6 mm/mm° C. to about 30×10-6 mm/mm° C., andmost preferably from about 9×10-6 mm/mm° C. to about 15×10-6 mm/mm° C.Other physical characteristics, at least in the case of a thick glass,may include: a density of about 2.42 g/cm³ to about 2.52 g/cm³, atensile strength of between about 75 to 200 N/sq.mm, a compressivestrength of between 500 and 1200 N/sq.mm, a modulus of elasticity ofbetween 60-80 GPa, a CLTE of about 9×10-6 mm/mm° C., and a visible lighttransmission of at least about 85%, preferably about at least 87%, morepreferably at least about 90%.

First Encapsulant Layer 124

In one example of an encapsulant layer, a first encapsulant layer 124may be disposed below the barrier layer 122 and generally above thephotovoltaic cell layer 110. It is contemplated that the firstencapsulant layer 124 may serve as a bonding mechanism, helping hold theadjacent layers together. It should also allow the transmission of adesirous amount and type of light energy to reach the photovoltaic cell110. The first encapsulant layer 124 may also function to compensate forirregularities in geometry of the adjoining layers or translated throughthose layers (e.g. thickness changes). It also may serve to allowflexure and movement between layers due to temperature change andphysical movement and bending. In a preferred embodiment, firstencapsulant layer 124 may consist essentially of an adhesive film ormesh, preferably an EVA (ethylene-vinyl-acetate), thermoplasticpolyolefin, polyurethanes, ionomers, silicon based polymers or similarmaterial. The preferred thickness of this layer range from about 0.1 mmto 1.0 mm, more preferably from about 0.2 mm to 0.8 mm, and mostpreferably from about 0.25 mm to 0.5 mm.

Photovoltaic Cell Layer 110

The photovoltaic cell layer 110 contemplated in the present inventionmay be constructed of any number of known photovoltaic cellscommercially available or may be selected from some future developedphotovoltaic cells. These cells function to translate light energy intoelectricity. The photoactive portion of the photovoltaic cell is thematerial which converts light energy to electrical energy. Any materialknown to provide that function may be used including crystallinesilicon, amorphous silicon, CdTe, GaAs, dye-sensitized solar cells(so-called Gratezel cells), organic/polymer solar cells, or any othermaterial that converts sunlight into electricity via the photoelectriceffect. However, the photoactive layer is preferably a layer ofIB-IIIA-chalcogenide, such as IB-IIIA-selenides, IB-IIIA-sulfides, orIB-IIIA-selenide sulfides. More specific examples include copper indiumselenides, copper indium gallium selenides, copper gallium selenides,copper indium sulfides, copper indium gallium sulfides, copper galliumselenides, copper indium sulfide selenides, copper gallium sulfideselenides, and copper indium gallium sulfide selenides (all of which arereferred to herein as CIGSS). These can also be represented by theformula Culn(1−x)GaxSe(2−y)Sy where x is 0 to 1 and y is 0 to 2. Thecopper indium selenides and copper indium gallium selenides arepreferred. Additional electroactive layers such as one or more ofemitter (buffer) layers, conductive layers (e.g. transparent conductivelayers) and the like as is known in the art to be useful in CIGSS basedcells are also contemplated herein. These cells may be flexible or rigidand come in a variety of shapes and sizes, but generally are fragile andsubject to environmental degradation. In a preferred embodiment, thephotovoltaic cell assembly 110 is a cell that can bend withoutsubstantial cracking and/or without significant loss of functionality.Exemplary photovoltaic cells are taught and described in a number of USpatents and publications, including U.S. Pat. Nos. 3,767,471, 4,465,575,US20050011550 A1, EP841706 A2, US20070256734 a1, EP1032051A2, JP2216874,JP2143468, and JP10189924a, incorporated hereto by reference for allpurposes.

The photovoltaic cell layer 110, for example as illustrated in FIG. 2B,may also include electrical circuitry, such as buss bar(s) 111 that areelectrically connected to the cells, the connector assembly component(s)300 and generally run from side to side of the PV device 10. This areamay be known as the buss bar region 311.

Second Encapsulant Layer 126

In another example of an encapsulant layer, a second encapsulant layer126 is generally connectively located below the photovoltaic cell layer110, although in some instances, it may directly contact the top layer122 and/or the first encapsulant layer 124. It is contemplated that thesecond encapsulant layer 126 may serve a similar function as the firstencapsulant layer, although it does not necessarily need to transmitelectromagnetic radiation or light energy.

Back Sheet 128

In an example of a protective layer there may be a back sheet 128 whichis connectively located below the second encapsulant layer 126. The backsheet 128 may serve as an environmental protection layer (e.g. to keepout moisture and/or particulate matter from the layers above). It ispreferably constructed of a flexible material (e.g. a thin polymericfilm, a metal foil, a multi-layer film, or a rubber sheet). In apreferred embodiment, the back sheet 128 material may be moistureimpermeable and also range in thickness from about 0.05 mm to 10.0 mm,more preferably from about 0.1 mm to 4.0 mm, and most preferably fromabout 0.2 mm to 0.8 mm. Other physical characteristics may include:elongation at break of about 20% or greater (as measured by ASTM D882);tensile strength or about 25 MPa or greater (as measured by ASTM 0882);and tear strength of about 70 kN/m or greater (as measured with theGraves Method). Examples of preferred materials include: glass plate;aluminum foil; poly (vinyl fluoride) (for example, commerciallyavailable as Tedlar® (a trademark of DuPont)); poly (ethyleneterephthalate); copolymer of tetrafluoroethylene and hexafluoroethylene(also known as “FEP”); poly (ethylene tetrafluoroethylene); poly(ethylene naphthalate); poly (methyl methacrylate); and polycarbonate,or a combination thereof.

Supplemental Barrier Sheet 130

In another example of a protective layer there may be a supplementalbarrier sheet 130 which is connectively located below the back sheet128. The supplemental barrier sheet 130 may act as a barrier, protectingthe layers above from environmental conditions and from physical damagethat may be caused by any features of the structure on which the PVdevice 10 is subjected to (e.g. For example, irregularities in a roofdeck, protruding objects or the like). It is contemplated that this isan optional layer and may not be required. It is also contemplated thatthis layer may serve the same functions as the body portion 200. In apreferred embodiment, the supplemental barrier sheet 130 material may beat least partially moisture impermeable and also range in thickness fromabout 0.25 mm to 10.0 mm, more preferably from about 0.5 mm to 2.0 mm,and most preferably from 0.8 mm to 1.2 mm. It is preferred that thislayer exhibit elongation at break of about 20% or greater (as measuredby ASTM D882); tensile strength or about 10 MPa or greater (as measuredby ASTM D882); and tear strength of about 35 kN/m or greater (asmeasured with the Graves Method). Examples of preferred materialsinclude thermoplastic polyolefin (“TPO”), thermoplastic elastomer,olefin block copolymers (“OBC”), natural rubbers, synthetic rubbers,polyvinyl chloride, and other elastomeric and plastomeric materials.Alternately the protective layer could be comprised of more rigidmaterials so as to provide additional roofing function under structuraland environmental (e.g. wind) loadings. Additional rigidity may also bedesirable so as to improve the coefficient of thermal expansion of thePV device 10 and maintain the desired dimensions during temperaturefluctuations. Examples of protective layer materials for structuralproperties include polymeric materials such polyolefins, polyesters,polyamides, polyimides, polyester amides, polysulfone, acetal, acrylic,polyvinyl chloride, nylon, polycarbonate, phenolic,polyetheretherketone, polyethylene terephthalate, epoxies, includingglass and mineral filled composites or any combination thereof.

The above described layers may be configured or stacked in a number ofcombinations, but it is preferred that the barrier layer 122 is the toplayer. Additionally, it is contemplated that these layers may beintegrally joined together via any number of methods, including but notlimited to: adhesive joining; heat or vibration welding; over-molding;or mechanical fasteners.

For the sake of clarity in view of some of the embodiments discussedbelow, the MPCA 100 can be further described in another fashion, as atwo part assembly. The first part, the MPCA subassembly 101, comprisingall the layers of the MPCA 100 (with the exception of the barrier layer122) and the second part being the barrier layer 122. The barrier layer122 may also be described as having a length “L_(BL)” and a width“W_(BL)”, for example as labeled in FIG. 2A. Preferably, the L_(BL)ranges from about 0.75 to about 1.25 times that of the L_(BP) discussedbelow, more preferably the lengths are within about 5-10% of each other.Also contemplated is that the MPCA subassembly 101 may have an overallCLTE (“subassembly CLTE”) that ranges from about 30×10-6 mm/mm° C. to150×10-6 mm/mm° C., more preferably about 50×10-6 mm/mm° C. to 100×10-6mm/mm° C.

Body Portion 200

It is contemplated that the body portion 200 may be a compilation ofcomponents/assemblies, but is preferably generally a polymeric articlethat is formed by injecting a polymer (or polymer blend) into a mold(with or without inserts such as the MPCA 100 or the other component(s)(e.g. connector component)—discussed later in the application), forexample as disclosed in currently pending International patentapplication No. PCT/US09/042,496, incorporated herein by reference. Thebody portion 200 functions as the main structural carrier for the PVdevice 10 and should be constructed in a manner consistent with this.For example, it can essentially function as a plastic framing material.It is contemplated that the body portion 200 should adhere to MPCA 100with an adhesion strength no less than the stress due to thermalexpansion.

It is contemplated that the compositions that make up the body portion200 also exhibit a coefficient of linear thermal expansion (“CLTE”) ofabout 0.5×10-6 mm/mm° C. to about 140×10-6 mm/mm° C., preferably ofabout 3×10-6 mm/mm° C. to about 50×10-6 mm/mm° C., more preferably fromabout 5×10-6 mm/mm° C. to about 30×10-6 mm/mm° C., and most preferablyfrom about 7×10-6 mm/mm° C. to about 15×10-6 mm/mm° C. Most desirably,the CLTE of the composition that makes up the body portion 200 shouldclosely match the CLTE of the barrier layer 122. Preferably the CLTE ofthe composition making up the body portion 200 disclosed herein are alsocharacterized by a coefficient of linear thermal expansion (CLTE) iswithin factor of 20, more preferably within a factor of 15, still morepreferably within a factor of 10, even more preferably within a factorof 5, and most preferably within a factor of 2 of the CLTE of thebarrier layer 122. For example, if the barrier layer 122 has a CLTE of9×10-6 mm/mm° C., then the CLTE of the molding composition is preferablybetween 180×10-6 mm/mm° C. and 0.45×10-6 mm/mm° C. (a factor of 20);more preferably between 135×10-6 mm/mm° C. and 0.6×10-6 mm/mm° C. (afactor of 15); still more preferably between 90×10-6 mm/mm° C. and0.9×10-6 mm/mm° C. (a factor of 10); even more preferably between45×10-6 mm/mm° C. and 1.8×10-6 mm/mm° C. (a factor of 5) and mostpreferably between 18×10-6 mm/mm° C. and 4.5×10-6 mm/mm° C. (a factor of2). Matching the CLTE's between the composition comprising the bodyportion 200 and the barrier layer 122 is important for minimizingthermally-induced stresses on the BIPV device during temperaturechanges, which can potentially result in cracking, breaking of PV cells,etc.

For some embodiments of the photovoltaic articles disclosed herein, thebarrier layer 122 includes a glass barrier layer. If the barrier layer122 includes a glass layer, the CLTE of the molding composition ispreferably less than 80×10-6 mm/mm° C., more preferably less than70×10-6 mm/mm° C., still more preferably less than 50×10-6 mm/mm° C.,and most preferably less than 30×10-6 mm/mm° C. Preferably, the CLTE ofthe novel composition is greater than 5×10-6 mm/mm° C.

When glass is used (as the barrier layer 122), the compositions of thebody material preferably have an elongation at break of at least 3% butnot typically more than 200%. It is also contemplated, when glass is notused, that the body material preferably has an elongation at break of atleast 100%, more preferably at least 200%, more preferably still atleast 300% and preferably no more than 500%. The tensile elongation atbreak of compositions were determined by test method ASTM D638-08 (2008)@ 23° C. using a test speed of 50 mm/min.

In a preferred embodiment, the body support portion 200 may comprise (besubstantially constructed from) a body material. This body material maybe a filled or unfilled moldable plastic (e.g. polyolefins,acrylonitrile butadiene styrene (SAN), hydrogenated styrene butadienerubbers, polyesters, polyamides, polyester amides, polyether imide,polyimides, polysulfone, acetal, acrylic, polyvinyl chloride, nylon,polyethylene terephthalate, polycarbonate, thermoplastic and thermosetpolyurethanes, synthetic and natural rubbers, epoxies, SAN, Acrylic,polystyrene, or any combination thereof). Fillers (preferably up toabout 50% by weight) may include one or more of the following:colorants, fire retardant (FR) or ignition resistant (IR) materials,reinforcing materials, such as glass or mineral fibers, surfacemodifiers. Plastic may also include anti-oxidants, release agents,blowing agents, and other common plastic additives. In a preferredembodiment, glass fiber filler is used. The glass fiber preferably has afiber length (after molding) ranging from about 0.1 mm to about 2.5 mmwith an average glass length ranging from about 0.7 mm to 1.2 mm.

In a preferred embodiment, the body material (composition(s)) has a meltflow rate of at least 5 g/10 minutes, more preferably at least 10 g/10minutes. The melt flow rate is preferably less than 100 g/10 minutes,more preferably less than 50 g/10 minutes and most preferably less than30 g/10 minutes. The melt flow rate of compositions were determined bytest method ASTM D1238-04, “REV C Standard Test Method for Melt FlowRates of Thermoplastics by Extrusion Plastometer”, 2004 Condition L(230° C./2.16 Kg). Polypropylene resins used in this application alsouse this same test method and condition. The melt flow rate ofpolyethylene and ethylene—α-olefin copolymers in this invention aremeasured using Condition E (190° C./2.16 Kg), commonly referred to asthe melt index.

In all embodiments, the compositions have flexural modulus of at least200 MPa, more preferably at least 400 MPa and most preferably at least700 MPa. According to the preferred embodiment where the MPCA 100includes a glass layer, the flexural modulus is preferably at least 1000and no greater than 7000 MPa. According to the second embodiment, theflexural modulus is no greater than 1500 MPa, more preferably no greaterthan 1200 MPa, most preferably no greater than 1000 MPa. The flexuralmodulus of compositions were determined by test method ASTM D790-07(2007) using a test speed of 2 mm/min. It is contemplated that thecompositions that make up the body portion 200 also exhibit acoefficient of linear thermal expansion (“body CLTE”) of about 25×10-6mm/mm° C. to 70×10-6 mm/mm° C., more preferably of about 27×10-6 mm/mm°C. to 60×10-6 mm/mm° C., and most preferably from about 30×10-6 mm/mm°C. to 40×10-6 mm/mm° C.

Preferably, the novel compositions are characterized as having an RTIElectrical and an RTI Mechanical Strength, each of which is at least 85°C., preferably at least 90° C., more preferably at least 95° C., stillmore preferably at least 100° C., and most preferably at least 105° C.

RTI (Relative Thermal Index) is determined by the test proceduredetailed in UL 746B (Nov. 29, 2000). Essentially a key characteristic ofthe plastic is measured at the start of the test (for instance tensilestrength), and then samples placed in at least four elevatedtemperatures (e.g. 130, 140, 150, 160 deg C.) and samples periodicallytested throughout several months. The reductions in key properties arethen tested, and working criteria established from comparison results ofknown materials of proven field service. The effective lifetime of theunknown, sample is then determined compared to the known material. RTIis expressed in degrees C. The test takes a minimum of 5000 hours tocomplete, and can be both time-consuming and costly.

Because RTI is an expensive and time-consuming test, a useful proxy forguiding the skilled artisan in selecting useful compositions is themelting point, as determined by differential scanning calorimetry (DSC).It is preferred that for the compositions set forth as useful herein, nomelting point is seen at temperatures less than 160° C. in differentialscanning calorimetry for a significant portion of the composition andpreferably no melting point is seen under 160° C. for the entirecomposition. The Differential Scanning calorimetry profiles weredetermined by test method ASTM D7426-08 (2008) with a heating rate of10° C./min. If a significant fraction of the injection moldingcomposition melts at temperatures below 160° C., it is unlikely that thecomposition will pass the UL RTI tests 746B for Electrical, MechanicalStrength, Flammability, and Mechanical Impact with a high enough ratingto adequately function when used in the PV device 10 (particularly whenuses as a BIPV).

It is contemplated that the body portion 200 may be any number of shapesand sizes. For example, it may be square, rectangular, triangular, oval,circular or any combination thereof. The body portion 200 may also bedescribed as having a length “L_(BP)” and a width “W_(BP)”, for exampleas labeled in FIG. 2A and may be as little as 10 cm and as much as 500cm or more, respectively. It may also have a thickness (t) that mayrange from as little as about 1 mm to as much as 20 mm or more and mayvary in different area of the body portion 200. Preferably, the bodyportion 200 can be described as having a body lower surface portion 202,body upper surface portion 204 and a body side surface portion 206spanning between the upper and lower surface portions and forming a bodyperipheral edge 208.

Connector Assembly

The connector assembly functions to allow for electrical communicationto and/or from the PV device 10. This communication may be inconjunction with circuitry connected to the photovoltaic cell layer 110or may just facilitate communication through and across the PV device 10via other circuitry. The connector assembly may be constructed ofvarious components and assemblies, and the main focus of this inventionrelates to the connector assembly component(s) 300 that are integral to(embedded within) the PV device. Generally, as illustrated in FIG. 3,this component 300 comprises a polymeric housing 310 and electricalleads 320 protruding into the PV device 10, although otherconfigurations are contemplated. Examples of preferred materials thatmake up the housing 310 include: Polymeric compounds or blends of PBT(Polybutylene Terephthalate), PPO (Polypropylene Oxide), PPE(Polyphenylene ether), PPS (Polyphenylene sulfide), PA (Poly Amid) andPEI (polyether imide) and these can be with or without fillers of up to65% by weight. It is contemplated that the compositions that make up thehousing 310 also exhibit a coefficient of linear thermal expansion(“CLTE”) in the flow direction of about 12×10-6 mm/mm° C. to 100×10-6mm/mm° C., more preferably of about 15×10-6 mm/mm° C. to 80×10-6 mm/mm°C., and most preferably from about 20×10-6 mm/mm° C. to 60×10-6 mm/mm°C.

It is contemplated that the housing 310 may be constructed of any numberof materials (as shown above), but preferably with materialcharacteristics such as: a tensile modulus that is at least about 0.1GPa, more preferably about 1 GPa, and most preferably about 10 GPa ormore; ultimate elongation value of about 1 percent, more preferablyabout 1.5 percent, and most preferably about 2.5 percent or more;coefficient of linear thermal expansion value of about 50×10-6 mm/mm°C., more preferably about 30×10-6 mm/mm° C., and most preferably about20×10-6 mm/mm° C.

In this illustrative connector housing 310, the housing may be furtherdefined as having a connector assembly lower surface portion 312, aconnector assembly upper surface portion 314 and a connector assemblyside surface portion 316 that spans between the upper and lower surfaceportions. The side surface portion 316 forming a connector assemblyperipheral edge 316′. Also located on the side surface portion 316 maybe flanges or projections 318.

In one embodiment, it is contemplated that the connector may alsoinclude a latching feature (not shown) which may function to positivelylatch a male and female connector portions together when installed. Thismay be a preferred configuration in the case where the intermediatelayer 500, interconnecting structural member 1500, relieving feature2500, or any combination thereof are disposed about the connectorhousing 310.

It is also contemplated that the “connector assembly” or “connectorhousing 310” described above could be some other component or objectthat is located in the same place in the PV device 10. The relationshipsdiscussed in the following sections also apply to this other componentor object.

Intermediate Layer 500

Intermediate layer or layers may be provided in the device 10. Theintermediate layer may function to aid in controlling stress/strain dueto the CLTE mismatch between the MPCA 100, the body portion and/or theconnector housing 310. It also may have the added benefit of aiding inthe overall dimensional stability of the device, particularly inrelation to the movement of the connector housing 310 over a desiredtemperature range (e.g. about −40° C. to 90° C.). Additionally, it mayexhibit moisture barrier properties, such as water vapor transmissionrate of preferably no greater than 50 g/m²-day at 38° C. In the casewherein the device 10 includes a relatively ridged polygonal barrierlayer 122 and at least one housing 310, it may function as a bridgebetween the two components.

It is contemplated that the intermediate layer 500 may comprise (besubstantially constructed from) an intermediate layer material. Thisintermediate layer material preferably may be selected from a groupconsisting of materials such as butyl rubber, ionomers, silicone rubber,polyurethane elastomers, polyolefin elastomers can serve this purpose orcomposites thereof. In one preferred embodiment, the layer material isformed from an encapsulant layer, the encapsulant as described above.

In one embodiment, where the layer 500 is designed to substantiallyabsorb stresses, it is contemplated that the intermediate layer 500 maybe constructed of any number of materials (as shown above), butpreferably with material characteristics such as: an tensile modulusthat is less than about 300 MPa, more preferably less than about 50 MPa,and most preferably about 1 MPa or less; ultimate elongation value ofabout 200 percent, more preferably about 500 percent, and mostpreferably about 1200 percent or more.

In another embodiment, where the layer 500 may both absorb and transferthe stresses, it is contemplated that the intermediate layer 500 may bea material with an elastic (tensile or Young's) modulus that is at leastwithin (plus or minus) about 15 percent of an elastic (tensile orYoung's) modulus of any of (or all of) the body portion 200, the MPCA100, and the connector housing 310, more preferably about 10 percent,and most preferably about 5 percent. In a preferred embodiment, thelayer elastic (tensile or Young's) modulus that is at least 5 percentless than that the body portion elastic (tensile or Young's) modulus orthe cell elastic (tensile or Young's) modulus. It is also contemplated,that in a preferred embodiment, the layer material has a layer ultimateelongation value at least 100 percent more than a body portion ultimateelongation value, a cell ultimate elongation value, or both. It is alsocontemplated, that in a preferred embodiment, the layer material has alayer yield strength value at least 5 percent lower than a body portionyield strength value and a cell yield strength value. In an alternativeway of defining the layer 500, it may preferably be characterized ashave a Young's modulus value ranging from about 50 to 5000 MPa, morepreferably from about 100 to 700 MPa, and most preferably from about 150to 400 MPa.

It is contemplated that the intermediate layer 500 may be a separatecomponent that is disposed between the MPCA 100 and the at least oneconnector 300 or may surround portions of the connector 300 and/or thetop layer 122. The layer 500 may also be integral to the MPCA 100.Illustrative examples are provided below.

Interconnecting Structural Member 1500

Interconnecting structural member or members may be provided in thedevice 10. The interconnecting structural member 1500 may function toaid in controlling stress/strain due to the CLTE mismatch between theMPCA 100, the body portion and/or the connector housing 310. It also mayhave the added benefit of aiding in the overall dimensional stability ofthe device, particularly in relation to the movement of the connectorhousing 310 over a desired temperature range (e.g. about −40° C. to 90°C.). In the case wherein the device 10 includes a relatively ridgedbarrier layer 122 and at least one housing 310, it may function as abridge between the two components.

It is contemplated that the structural member 1500 may be constructed ofany number of materials, but preferably constructed of a material with atensile modulus that is at least about 1.25× that of a tensile modulusof the body portion, more preferably about 1.5×, and most preferablyabout 2× or more. For example, using an inorganic material (such as asteel reinforcement member that may have a modulus of about 206 GPa)this range could be up to 200×. It is also contemplated that theinterconnecting structural member may be a material with a tensilemodulus that is virtually equivalent to a tensile modulus of the toplayer or as much as about 4× thereof. In one preferred embodiment, thestructural member 1500 tensile modulus is at least within about 5 to 30percent of a tensile modulus of the top layer 122, more preferably about7 to 20 percent, and most preferably about 10 to 15 percent. In apreferred embodiment, the interconnecting structural member 1500 maycomprise (be substantially constructed from) an interconnectingstructural member material. The interconnecting structural membermaterial preferably may be selected from a group consisting of glass,metals, ceramics, aluminum, steel, carbon fiber, filled and unfilledpolymers, or composites thereof.

It is contemplated that the structural member 1500 may be integrated inthe body, or may be a separate component that is disposed between theMPCA 100 and the at least one connector 300 or may be integral to theconnector 300. The structural member 1500 may be used anywhere localizedstrain exist to minimize the strain. (e.g. not only between the MPCA 100and a connector) It is also contemplated that the structural member 1500may include locating features that may aid in the positioning of itselfor additional components of the device 10.

Geometric and Material Property Relationships

It is believed that the choices of materials used in the construction ofthe PV device 10 and its constituent components and both the geometricand physical property relationships have an effect on overallperformance of the system (e.g. durability and ease of assembly ofmultiple PV devices together). Balancing the needs of ease ofmanufacture, costs and/or product performance requirements may driveunique material choices and component design (e.g. the use of at leastone interconnecting member described below; the use of at least oneinterconnecting structural member described below; and/or relievingfeature(s) 2500 therein). The present invention contemplates thesefactors and provides a unique solution to achieve a desired result.

It is contemplated that it may be desirous to match physical propertiesas much as feasible of the various components such that the completesystem can work in harmony (e.g. all or most components constructed fromsimilar materials or material families). Where this cannot be achievedfully, it is contemplated that unique geometric designfeatures/components (e.g. interconnecting members; interconnectingstructural members; relieving features, and/or geometric designs ofindividual components) may be needed. Of particular interest is therelationship of choice of material properties of the body portion 200,the MPCA 100 as a whole (and in some case particularly the barrier layer122), and the connector 300, and the geometric relationship to eachother.

MPCA, Body, and/or Connector Relationships

This section concentrates on certain aspects of the relationshipsbetween the MPCA 100, the body portion 200, and/or the connector housing310 and interconnecting intermediate layer(s) 500 therein. Theintermediate layer may be disposed in the panel or in the body portionadapted to allow controlled elastic deformation of the photovoltaicdevice 10 over a temperature range (typically near to or just below theouter surface of the body portion 200). Typically, the temperature rangeis from about −40° C. to 90° C. It is believed that this deformation isdue in large part to the CLTE differences between the body portion 200(and the connector, when present) and the MPCA 100. In other words, theintermediate layer provides a mechanism for dissipating and/or directingstresses caused by the CLTE differences. It is also contemplated thatthe smaller the CLTE differences between the respective components, thesmaller (e.g. dimensionally) or fewer areas where the intermediate layer(s) 500 may be required. For example, when the CLTE differences betweenthe respective components are greater than 5 percent, it is believedthat at least one area of intermediate layering is required.

This section also concentrates on certain aspects of the relationshipsbetween the MPCA 100, the body portion 200, and/or the connector housing310 and interconnecting structural member(s) 1500 therein. Theinterconnecting structural member disposed in the panel or in the bodyportion adapted to allow controlled elastic deformation of thephotovoltaic device 10 over a temperature range (typically near to orjust below the outer surface of the body portion 200). Typically, thetemperature range is from about −40° C. to 90° C. It is believed thatthis deformation is due in large part to the CLTE differences betweenthe body portion 200 (and the connector, when present) and the MPCA 100.In other words, the interconnecting structural member provides amechanism for dissipating and/or directing stresses caused by the CLTEdifferences.

This section concentrates on certain aspects of the relationshipsbetween the MPCA 100, MPCA subassembly 101 and the body portion 200.Several illustrative examples and preferred embodiments are detailedherein. One skilled in the art should realize that these examples shouldnot be limiting and the present invention contemplates other potentialconfigurations.

It is believed that it may be desirous to control the overall shape ofthe PV device 10, particularly to control the cant (or cupping) of thebody portion 200 along its width W_(BP). Cupping or cant may be animportant consideration when one PV device 10 is laid on (or installedover) another PV device 10 on a surface (e.g. a build structure 451), asillustrated in FIGS. 21, 24 and 25.

FIG. 25 is an illustrative example of a PV device 10 that is not cuppedand would not be desirous. FIG. 24 shows a PV device 10 that is cuppedin a desirable fashion. The amount of cupping 454 (e.g. distance fromthe plane of the next lower structure 451 or another PV device10—cupping value) preferably ranges from about 3.0 mm to about 30 mm,more preferably from about 5.0 mm to 25.0 mm, and most preferably fromabout 7.0 mm to 15 mm.

It is believed that to effectuate manufacturing a PV device 10 thatmeets the some or all of the needs discussed above, additional designconsiderations may be necessary. The present invention contemplates thatgiven the material and geometric relationships discussed in the previoussection, it may be beneficial to include a bending region 210. Ofparticular note is that as the percent difference in the subassemblyCLTE to that of the body portion material increase, the need for thebending region increase. These ratios and their influence on componentstresses are significant in isolation of stress loadings. It may beadvantageous to locate these regions in such a way that manufacturingand installation loadings do not combine with stresses due to thermalloadings and the relative CLTE's of the materials. This may also occurat a critical region of the device that includes critical electricalcomponents (connector, bus bars, etc.) that influence the part todisadvantaged thicknesses and lengths. Examples of the location and/orthe configuration of the bending region 210 are presented below. It iscontemplated that any or all combinations of aspects from each examplemay be combined if so desired.

It is preferred that this bending region be located very near (e.g.within about 25.0 mm) the fastening location (or fastening zone 450) ofthe device 10, such that when it is fastened (e.g. with mechanicalfasteners such as nails 452, screws or the like) to the mounting surface(e.g. building structure 451) that the uppermost and lowermost edges arein full contact with the mounting surface or the other devices. It isbelieved that this maybe important for many aspects of a roofing deviceand a photovoltaic device. Examples include water sealability,resistance to wind loading, stability in wind and vibration, andmaintaining a uniform position on the mounting surface throughenvironmental and servicing situations. It is therefore very desirous tohave a bending region such that edges are properly pre-loaded to meetthese needs. Without the bending region, excessive force may be neededto fasten the device to the mounting structure. Alternately, if the parthas insufficient bending resistance or improper bend (or cant),sufficient edge contact cannot be maintained.

In the case where at least one connector 300 is present in the device10, the relationship of material properties between of the connectorhousing 310 and the rest of the respective components are contemplated.In one preferred embodiment, the layer elastic (tensile or Young's)modulus may be at least about equivalent to, more preferably less thanand most preferably about 5 percent less than the frame (body portion)elastic (tensile or Young's) modulus, a connector elastic (tensile orYoung's) modulus, or both. It is also contemplated in another preferredembodiment that the layer elastic (tensile or Young's) modulus value canbe between the frame (body portion) elastic (tensile or Young's) modulusvalue and the cell elastic (tensile or Young's) modulus value. In yetanother preferred embodiment, the layer coefficient of thermal expansionvalue is at least equivalent to, more preferably higher than and mostpreferably about 10 percent higher than the frame (body portion)coefficient of thermal expansion value and the connector coefficient ofthermal expansion value. In yet another preferred embodiment, the layerultimate elongation value at least about 50 percent more than, morepreferably about 80 percent, and most preferably about 100 percent morethan the body portion ultimate elongation value, the connector ultimateelongation value, or both.

It is contemplated that the layer material adheres to the variouscomponents that it comes into contact with, with a preferred minimumadhesion value of at least about 0.5 joules/m², more preferably about 1joules/m², and most preferably about 2 joules/m² as adhered to thethree-dimensional multi-layered photovoltaic cell assembly, the bodyportion or the connector housing. It is also contemplated that it may bedesirous that the layer material have a greater adhesion (e.g. 5 percentor greater) to one component versus another component. For example, itmay be preferred that the material of the intermediate layer adheres tothe connector housing more than to the frame (body portion) assemblyand/or adheres to the photovoltaic cell assembly more than to the frame(body portion) assembly. It is contemplated that that adhesion to thecomponents, other than the frame assembly (body portion) may bepreferred due to the importance of having a lower water vaporpenetration to the electrical components in the device 10.

It is also contemplated that the smaller the CLTE differences betweenthe respective components, the smaller (e.g. dimensionally) or fewernumbers of interconnecting structural member(s) 1500 may be required.For example, when the CLTE differences between the respective componentsis greater than 5 percent, it is believed that at least oneinterconnecting structural member and/or at least one relieving featureis required.

It is contemplated that the structural member 1500 may be directlymechanically interlocked (for example as shown in FIG. 9B) into thedevice 10, may be interlocked via an adhesive system, or a combinationthereof. In the case of an adhesive system, the adhesive chosen shouldhave characteristics such as having a tensile yield strength greaterthan a tensile yield strength of the connector 300 and a tensile yieldstrength of the body 200. Other desired characteristics may include anadhesive system, the adhesive chosen to have an adhesion strength noless than the stress due to thermal expansion. It is contemplated thatthe joint between the components, where the adhesive is disposed, shouldbe at least a single or double lap joint, or any such joint that isdesigned to minimize interfacial stresses.

Several illustrative examples and preferred embodiments are detailedherein. One skilled in the art should realize that these examples shouldnot be limiting and the present invention contemplates other potentialconfigurations.

In a first example of an intermediate layer 500, as shown in FIGS. 4A-B,the intermediate layer 500 is disposed between the outer surface 204 ofthe body portion 200 and MPCA 100 and extends around the connector 300and to the edge of the barrier layer 122. Preferably the layer 500 has athickness I_(t) of at least in the immediate vicinity (e.g. within about5.0 mm) of the connector 300 and the layer 122 of at least about 50percent of their respective thicknesses (C_(t), B_(t)).

In a second example, as shown in FIGS. 5A-B, a first intermediate layerportion 500 is disposed between the outer surface 204 of the bodyportion 200 and MPCA 100 about the upper edge of the layer 122. A secondand third intermediate layer portion 500 extends around the connector300. Preferably the layer 500 has a thickness I_(t) of at least in theimmediate vicinity (e.g. within about 5.0 mm) of the connector 300 andthe layer 122 of at least about 50 percent of their respectivethicknesses (C_(t), B_(t)).

In a third example, as shown in FIGS. 6A-C, a first intermediate layerportion 500 is disposed between the body portion 200 and MPCA 100 aboutthe upper edge of the layer 122 and is coextensive with the body uppersurface portion 204. In 6B, the layer portion 500 is shown as beingformed from encapsulant layer 124. In 6C, layer 500 is a separatecomponent and/or material from that of layer 124. In this example, thedevice 10 is shown without the connectors 300; it is contemplated thatthey may be included if desired.

In a fourth example, as shown in FIGS. 7A-C, a first intermediate layerportion 500 is disposed between the body portion 200 and MPCA 100 andcompletely separates the two components, coextensive with the body lowersurface portion 202, and body upper surface portion 204. In 7B, thelayer portion 500 is shown as being formed from encapsulant layer 124and/or 126. In 7C, layer 500 is a separate component and/or materialfrom that of layers 124 and/or 126. In this example, the device 10 isshown without the connectors 300; it is contemplated that they may beincluded if desired.

In a first illustrative example of a interconnecting structural member1500, shown in FIG. 8, the body portion 200 and a portion of the barrierlayer 122 are joined (e.g. are in contact) along the barrier layerperipheral edge 222. In this example, the barrier layer is comprised ofa glass with physical properties for the glass, as disclosed in previoussections of the specification. In this example, the barrier layerperipheral edge 222 has rounded barrier perimeter corners 420. A set ofopposing connector housings 310 are disposed along the outer edge of thebody portion 200. Also included is a singular interconnecting structuralmember 1500 disposed in the body portion 200.

In a first preferred embodiment, this interconnecting structural member1500 is located at least within a distance D_(R) of the barrier layer ofthe three-dimensional multi-layered photovoltaic cell assembly along atleast about 50 percent (preferably at least about 70 to 90 percent) ofthe peripheral edge 222 between the corners 420. Preferably, distanceD_(R) is about 0 to 12.0 mm, more preferably about 0.5 mm to 7.0 mm, andmost preferably about 1.0 to 5.0 mm. In this illustrative example, theinterconnecting structural member 1500 is also disposed along at leastone or more sides of the connector housing 310. Preferably, disposedwithin about 0.5 to 5.0 mm of a peripheral edge of the connectorhousing, although it is contemplated that it may directly abut thehousing 310 (or the peripheral edge 222).

In this embodiment, the interconnecting structural member 1500 iscomprised of a plate like structure that has a general thickness M_(T)of about 1.0 mm to 6.0 mm. It is contemplated that the thickness may beuniform across the structural member 1500, although it may beadvantageous for the thickness to be greater in the vicinity of thehousing 310 and/or the peripheral edge 222 (e.g. equivalent to or atleast about 75 percent the thickness of the housing 310 and/or theperipheral edge 222 respectively).

In a second illustrative example, shown in FIGS. 9A-B, the device 10 isconfigured similarly to that of the first example, with the exception ofthe number of and location of the interconnecting structural member1500. In this illustrative embodiment, there two interconnectingstructural members 500. They are integral to the connector housings 310and project downward to the barrier layer 122. The structural member1500 includes a locking portion 510 which overlaps the barrier layer onopposing, sides. In this example, it is contemplated that in the area ofthe locking region 510, an adhesive may be at least partially disposedbetween the structural member 1500 and the barrier layer 122.Preferably, the locking portion is located on at least two planes sothat lateral forces in any direction will not cause it to becomedislodged.

In a third illustrative example, shown in FIG. 10, the interconnectingstructural member is mechanically interlocked with the barrier layer 122and the connector housing 310. In this embodiment, the interconnectingstructural member has locking features 520 that are adapted to mate witha barrier locking feature 123 and a connector locking feature 311. It iscontemplated that this may be a line to line fit, a press fit, or havean intermediate adhesive layer disposed in-between. It is contemplatedthat any number of shapes could be utilized to provide the lockingfeatures 520 and the present example is not intended to be limiting.

In a first illustrative example of a relieving feature 2500, shown inFIG. 12, the body portion 200 and a portion of the barrier layer 122 arejoined (e.g. are in contact) along the barrier layer peripheral edge222. In this example, the barrier layer is comprised of a glass withphysical properties for the glass, as disclosed in previous sections ofthe specification. In this example, the barrier layer peripheral edge222 has rounded barrier perimeter corners 420. A set of opposingconnector housings 310 are disposed along the outer edge of the bodyportion 200. Also included is a singular relieving feature 2500 disposedin the body portion 200.

In a first preferred embodiment, this relieving feature 2500 is locatedat least within a distance D_(R) of the barrier layer of thethree-dimensional multi-layered photovoltaic cell assembly along atleast about 50 percent (preferably at least about 70 to 90 percent) ofthe peripheral edge 222 between the corners 420. Preferably, distanceD_(R) is about 10.0 to 30.0 mm, more preferably about 12.5 mm to 25.0mm, and most preferably about 15.0 to 20.0 mm. In this illustrativeexample, the relieving feature 2500 is also disposed above the connectorhousing 310. Preferably, disposed within about 5.0 to 15.0 mm of a topperipheral edge of the connector housing, although it is contemplatedthat it may directly abut the housing 310.

In this embodiment, the relieving feature is comprised of a localizedthinning of the body portion 200. Preferably, the localized thinning hasa depth of at least 50 percent that of a depth of the body portion 200and constitutes a channel 510 with a profile C_(P) and a width C_(W). Ina preferred embodiment, the width C_(W) is at least about 1.0 mm and asmuch as about 15.0 mm, more preferably about 2.5 mm to 12.5 mm, and mostpreferably about 3.5 to 8.0 mm. It is contemplated that both thelocation of the relieving feature 2500 and its width C_(W) can beoptimized. Examples shown in FIGS. 11A-F are illustrative and should notbe considered as limiting.

In a second illustrative example, shown in FIG. 13, the device 10 isconfigured similarly to that of the first example, with the exception ofthe number of and location of the relieving feature 2500. In thisillustrative embodiment, there are four relieving features 2500. Theyare disposed in the body portion 200 and span from the inside corners430, 432 of the connector housings towards the barrier layer 122. Inthis embodiment, it is preferred that the features 2500 that abut thelower inside corners of the connector housings 310 are directed towardsthe rounded barrier perimeter corners 420 (somewhere in the curved arc).It is also preferred that the features 2500 that abut the upper insidecorners of the connector housings 310 are directed towards the center ofthe device 10. More preferably at an angle α that has a value betweenabout 15 an 65 degrees, even more preferably between about 30 and 45degrees. The distal end of the feature (opposite the connector housing310) is preferably about 10.0 to 30.0 mm from the peripheral edge 222,more preferably about 12.5 mm to 25.0 mm, and most preferably about 15.0to 20.0 mm.

In a third illustrative example, shown in FIG. 14, the relieving featureis disposed in the barrier layer 122. In this embodiment, the relievingfeature has a depth that is at least equivalent to the thickness of thebarrier layer 122 and spans across at least 25% of the width W_(BL)(preferably across about 100%). It is also preferable that the channelhave a profile similar to that as shown in FIG. 11E. In this embodiment,it is preferable that at least the bottom of the relieving featurechannel is filled with an elastomeric barrier material to provide atleast some environmental barrier protection (a low modulus, highadhesion and high elongation material). For example, materials such asbutyl rubber, ionomers, silicone rubber, polyurethane elastomers,polyolefin elastomers can serve this purpose. The use of such a filleris also contemplated for any of the other embodiments or examples.

In a fourth illustrative example, shown in FIG. 15, the device 10 isconfigured similarly to that of the first example, with the exception ofthe number of and location of the relieving feature 2500. In thisillustrative embodiment, there are six relieving features 2500. They aredisposed in the body portion 200 and are channels that run normal to theperipheral edge 222, from the peripheral edge 222 to a point near thetop of the connector housing 310. They may be spaced apart about equallyacross the device 10, but other spacing locations are contemplated.

In a fifth illustrative example, shown in FIG. 16, the device 10 isconfigured similarly to that of the first example, again with theexception of the number of and location of the relieving feature 2500.In this illustrative embodiment, there are two relieving features 2500.They are disposed in the body portion 200 and are channels that extendfrom the peripheral edge 222 (preferably in the rounded barrierperimeter corners 420) to a lower outside corner of the connectorhousing 310 (preferably at the outside periphery of the device 10).

In a first illustrative example of unique individual component geometry,shown in FIGS. 17, 18 and 19, the body portion 200 and a portion of thebarrier layer 122 are joined (e.g. are in contact) along a segment 400of the barrier layer peripheral edge 222 (a segment 400 of the perimeterof the barrier's edge). This area where the two parts come together maybe known as the interface region 410. It is contemplated that thisinterface may span across the entire barrier profile 230 or only aportion thereof or onto a portion of the barrier lower surface portion224, the barrier upper surface portion 226, or both. In this example,the barrier layer is comprised of a glass with physical properties forthe glass, as disclose in previous sections of the specification. Inthis example, the barrier layer peripheral edge 222 has rounded barrierperimeter corners 420 within the segment 400. It is contemplated thatthe L_(BL) may be equivalent to the L_(BP) and that barrier layerperipheral edge 222 need not have rounded barrier perimeter corners 420within the segment 400.

In a first preferred embodiment, these rounded corners 420 are locatedat least in the area of the segment 400 that faces the largest portionof the body portion 200, which can be clearly seen in the figures.Preferably, the rounded barrier perimeter corners 420 have a radius 422of about 2.0 to 50.0 mm, more preferably about 12.5 mm to 30.0 mm, andmost preferably about 17.0 to 27.0 mm.

In a second preferred embodiment, the radius 422 of the rounded barrierperimeter corners 420 is determined as a ratio of the L_(BL) (at leastas measured within about 25.0 mm of the interface region 410) to theL_(BP), calculated as (L_(BL)/L_(BP)). Preferably, the ratio is about0.00345 to 0.0862, more preferably about 0.01000 to 0.0500, and mostpreferably about 0.0400 to 0.0450.

When glass is used (as the barrier layer 122) as in this example, thecompositions of the body material preferably have an elongation at breakof at least 3% but not typically more than 50%. It is also contemplated,when glass is not used, that the body material preferably has anelongation at break of at least 100%, more preferably at least 200%,more preferably still at least 300% and preferably no more than 500%.The tensile elongation at break of compositions were determined by testmethod ASTM D638-08 (2008)#23° C. using a test speed of 50 mm/min.

In a second illustrative example, shown in FIGS. 3 and 20, the bodyportion 200 and the barrier layer 122 geometric relationships aremaintained. In this example a connector housing 310 is present. It iscontemplated and preferred that the connector assembly peripheral edgethat is closest to the interface region has at least one roundedconnector corner 430 with a radius 432. Generally, the rounded connectorcorner 430 may have a radius 432 of about 0.1 mm to 15.0 mm, morepreferably about 0.5 mm to 5.0 mm, and most preferably about 1.0 mm to4.0 mm. In this example, the at least one component of the connectorassembly (e.g. connector housing 310) is disposed away from theinterface region by a disposal distance 440 (e.g. closest pointtherebetween).

In a first preferred embodiment, a desirous disposal distance 440 (inmm) can be calculated as a relationship between various physicalproperties of some of the component materials. Preferably, the disposaldistance 440 is greater than or equal to X*(body CLTE/barrier CLTE)+C.In a preferred embodiment, X is a constant that ranges from about 1.0 to4.0, more preferably from about 2.5 to 3.8, and most preferably fromabout 3.0 to 3.75. In a preferred embodiment, C is a constant thatranges from about 0.5 to 10.0, more preferably from about 1.0 to 5.0,and most preferably from about 1.25 to 3.0.

In a second preferred embodiment, a desirous disposal distance 440 canbe calculated as ratio of the L_(BP) (at least as measured within about25.0 mm of the rounded connector corner 430) to the disposal distance440 (disposal distance 440/L_(BP)=ratio). Preferably, the ratio is about0.02 to 0.1, more preferably about 0.03 to 0.08, and most preferablyabout 0.035 to 0.044.

In a third preferred embodiment, the radius 432 (of the at least onerounded connector corner 430) is determined as a ratio of the radius 432to the L_(BP) (at least as measured within about 25.0 mm of the roundedbarrier perimeter corners 420) (radius 432/L_(BP)=ratio). Preferably,the ratio is about 0.000172 to 0.0259, more preferably about 0.001000 to0.015000, and most preferably about 0.001724 to 0.00517.

Other relationships contemplated in the present invention include: Thedistance between the interface region 410 and the buss bar region 311relative to the length (L_(BP), particularly within about 25.0 mm of theregion 410) of the body portion 200 can be expressed as a ratio.Preferably, this ratio ranges from about 0.00348 to 0.0438, morepreferably from about 0.01000 to 0.03000, and most preferably from about0.01500 to 0.02500. Furthermore, the relationship of the thickness ofthe body portion (T) in relation to the length (L_(BP), particularlywithin about 25.0 mm of the region 410) is contemplated as a ratio(T/L_(BP)). Preferably, this ratio ranges from about 0.0017 to 0.035,more preferably from about 0.0150 to 0.030, and most preferably fromabout 0.0100 to 0.0200.

In a first illustrative example of bending/cant, shown in FIG. 22, abending region 210 is created with the PV device 10 by reducing the bodyportion 200 thickness (at least locally) and wherein the MPCAsubassembly 101 steps in a direction towards the top surface of the bodyportion 200. It is contemplated that this bending region 210 preferablystarts at least about 5.0 mm away from the interface region andcontinues to at least about to the top of the MPCA subassembly 101,although it could continue further up the body portion 200.

In a first preferred embodiment, the bending region 210 generally spansacross at least about 70% of the length of PV device 10 in an area thatthe connector housing 310 is and/or the area where the buss bar region311 is located. The body section 200, in the bending region 210, has athickness (“T_(BR)”) of about 2.5 mm to 4.0 mm.

In a second preferred embodiment, a starting point 211 for the bendingregion 210 is located a distance (in mm) from the interface region andis greater than or equal to X′*(body CLTE/barrier CLTE)+C′. In thispreferred embodiment, X′ is a constant that ranges from about 1.0 to5.0, more preferably from about 2.5 to 4.8 and most preferably has avalue of 3.75. In this preferred embodiment, C′ is a constant thatranges from about 1.0 to 8.0, more preferably from about 2.0 to 6.0 andmost preferably from about 3.0 to 5.0.

In a third preferred embodiment, the preferred thickness (“T_(BR)”) isrelated to the ratio of the subassembly CLTE to the body CLTE(subassembly CLTE/body CLTE). The thickness (“T_(BR)”) being about 0.3to 1.9 times this ratio. Preferably, the ratio is about 1.0 to 5.0, morepreferably about 1.5 to 3.5, and most preferably about 1.8 to 2.1.

In a second illustrative example, shown in FIG. 23, the bending region210 is similar to that of the first example, but the bending region doesnot continue to the top of the MPCA subassembly 101. The bending regiononly extends about 50 to 75% of the way to the top of the MPCAsubassembly 101 (e.g. in the direction of the width W_(BP)).

It is contemplated that the embodiments or examples described above maynot be mutually exclusive and may be used in combination with eachother.

Unless stated otherwise, dimensions and geometries of the variousstructures depicted herein are not intended to be restrictive of theinvention, and other dimensions or geometries are possible. Pluralstructural components can be provided by a single integrated structure.Alternatively, a single integrated structure might be divided intoseparate plural components. In addition, while a feature of the presentinvention may have been described in the context of only one of theillustrated embodiments, such feature may be combined with one or moreother features of other embodiments, for any given application. It willalso be appreciated from the above that the fabrication of the uniquestructures herein and the operation thereof also constitute methods inaccordance with the present invention.

Unless otherwise stated, the coefficient of linear expansion (“CLTE”)for the materials and assemblies disclosed herein is determined on a TAInstruments TMA Model 2940 by test method ASTM E1824-08 (2008) in atemperature range of −40° C. and 90° C., at 5° C. per minute, using thestandard software provided with the instrument. The skilled artisan willappreciate that a composition may exhibit temperature ranges where theCLTE changes from other regions as the material undergoes thermaltransitions. In such a case, the preferred ranges for CLTE above referto the largest measured CLTE for the compositions, assemblies and/orbarrier layer 122. A photovoltaic device may include many differentmaterials, including materials with very different CLTE. For example, aPV assembly may include solar cells, metal conductors, polymericencapsulants, barrier materials such as glass, or other disparatematerials, all with different CLTE's. The CLTE of a PV assembly may bedetermined by measuring the dimensions of the assembly at a number oftemperatures between −40° C. and 90° C. This temperature range is alsoassumed for all other physical properties (testing) unless otherwisespecified.

The preferred embodiment of the present invention has been disclosed. Aperson of ordinary skill in the art would realize however, that certainmodifications would come within the teachings of this invention.Therefore, the following claims should be studied to determine the truescope and content of the invention.

Any numerical values recited in the above application include all valuesfrom the lower value to the upper value in increments of one unitprovided that there is a separation of at least 2 units between anylower value and any higher value. As an example, if it is stated thatthe amount of a component or a value of a process variable such as, forexample, temperature, pressure, time and the like is, for example, from1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it isintended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc.are expressly enumerated in this specification. For values which areless than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1as appropriate. These are only examples of what is specifically intendedand all possible combinations of numerical values between the lowestvalue and the highest value enumerated are to be considered to beexpressly stated in this application in a similar manner.

Unless otherwise stated, all ranges include both endpoints and allnumbers between the endpoints. The use of “about” or “approximately” inconnection with a range applies to both ends of the range. Thus, “about20 to 30” is intended to cover “about 20 to about 30”, inclusive of atleast the specified endpoints.

The disclosures of all articles and references, including patentapplications and publications, are incorporated by reference for allpurposes. This application is a national phase filing under 35 USC §371from PCT Application serial number PCT/US2011/1064393 filed on 12 Dec.2011, and claims priority therefrom. This application further claimspriority from US Provisional Application 61/424,325 flied 17 Dec. 2010both incorporated herein by reference.

The term “consisting essentially of” to describe a combination shallinclude the elements, ingredients, components or steps identified, andsuch other elements ingredients, components or steps that do notmaterially affect the basic and novel characteristics of thecombination.

The use of the terms “comprising” or “including” describing combinationsof elements, ingredients, components or steps herein also contemplatesembodiments that consist essentially of the elements, ingredients,components or steps.

Plural elements, ingredients, components or steps can be provided by asingle integrated element, ingredient, component or step. Alternatively,a single integrated element, ingredient, component or step might bedivided into separate plural elements, ingredients, components or steps.The disclosure of “a” or “one” to describe an element, ingredient,component or step is not intended to foreclose additional elements,ingredients, components or steps. All references herein to elements ormetals belonging to a certain Group refer to the Periodic Table of theElements published and copyrighted by CRC Press, Inc., 1989. Anyreference to the Group or Groups shall be to the Group or Groups asreflected in this Periodic Table of the Elements using the IUPAC systemfor numbering groups.

What is claimed is:
 1. A photovoltaic device comprising: a three-dimensional multi-layered photovoltaic cell assembly in the form of a panel including at least: a top surface, a bottom surface, and a peripheral edge extending between and connecting the top surface to the bottom surface, the peripheral edge including a length and a width; further including a barrier layer comprising a rigid material that is transparent or translucent; a body portion comprising: filled or unfilled moldable plastic material, a main body portion, a first frame portion, and a second frame portion extending from an opposite side of the main body portion as the first frame portion and an empty region located between the first frame portion and the second from portion; and wherein the body portion is at least partially surrounding a portion of the top surface and the peripheral edge of the three-dimensional multi-layered photovoltaic cell assembly, and the main body portion has a bottom peripheral edge extending between and connecting the first frame portion and the second frame portion; a relieving feature disposed in the main body portion that is a localized thinning of the main body portion, the localized thinning of the main body portion extending along the bottom peripheral edge of the main body portion and being located outside of the peripheral edge of the three-dimensional multi-layered photovoltaic cell assembly so that the relieving feature allows elastic deformation of the photovoltaic device over a temperature range, wherein the localized thinning has a depth of at least 50 percent that of a depth of the three-dimensional multi-layered photovoltaic cell assembly, and wherein the localized thinning of the main body portion is a channel; and at least one electrical connector assembly with a connector housing, the connector housing having an outer surface having a housing top surface, a housing bottom surface, and a housing peripheral edge connecting the housing top surface and the housing bottom surface, and the at least one connector housing is located between a portion of the relieving feature and the bottom peripheral edge of the main body portion.
 2. The photovoltaic device according to claim 1, wherein the at least one electrical connector assembly is two electrical connector assemblies disposed on opposite sides of the three dimensional multi-layered photovoltaic cell assembly.
 3. The photovoltaic device according to claim 1, wherein the relieving feature is disposed in the main body portion within 15.0 mm of the barrier layer of the three-dimensional multi-layered photovoltaic cell assembly along at least 50 percent of a top peripheral edge of the multi-layered photovoltaic cell assembly, and wherein the top peripheral edge of the three-dimensional multi-layered photovoltaic cell assembly is located proximate to the bottom peripheral edge of the main body portion.
 4. The photovoltaic device according to claim 1, wherein the housing peripheral edge of the connector housing includes a top peripheral edge and a bottom peripheral edge and the bottom peripheral edge is located proximate to the three-dimensional multi-layered photovoltaic cell assembly and the top peripheral edge is located opposite the bottom peripheral edge, and the relieving feature is disposed in the main body portion within 5.0 mm of the top peripheral edge of the connector housing.
 5. The photovoltaic device according to claim 1, wherein the barrier layer is comprised of a glass with a thickness of 1.0 to 5.0 mm.
 6. The photovoltaic device according to claim 1, wherein at least the body portion is comprised of: a body material with a body coefficient of linear thermal expansion, the body portion with a body lower surface portion, body upper surface portion and a body side surface portion spanning between the upper and lower surface portions and forming a body peripheral edge, wherein at least a portion of the body portion abuts to a segment of a barrier layer peripheral edge at an interface region; wherein the at least one electrical connector assembly further includes at least one component at least partially embedded in the body side surface portion and the connector assembly component includes a connector assembly lower surface portion, a connector assembly upper surface portion and a connector assembly side surface portion spanning between the upper and lower surface portions which forms a connector assembly peripheral edge, wherein the connector assembly peripheral edge that is closest to the interface region has at least one rounded connector corner, and the connector assembly is in electrical communication with a photovoltaic cell layer of the photovoltaic cell assembly.
 7. The photovoltaic device according to claim 1, wherein: the multilayered photovoltaic cell assembly is comprised of: the barrier layer with a barrier layer material having a barrier coefficient of linear thermal expansion and a photovoltaic cell layer disposed inboard of a barrier layer peripheral edge, the barrier layer including a barrier lower surface portion, a barrier upper surface portion and a barrier side surface portion spanning between the upper and lower surface portions with a barrier profile between the upper and lower surface portions and a barrier perimeter spanning about the barrier layer which forms the barrier layer peripheral edge; the body portion comprised of: a body material with a body coefficient of linear thermal expansion, the body portion with a body lower surface portion, body upper surface portion and a body side surface portion spanning between the upper and lower surface portions and forming a body peripheral edge, wherein at least a portion of the body portion abuts to a segment of the barrier layer peripheral edge at an interface region.
 8. The photovoltaic device according to claim 1, comprising an intermediate layer comprised of a layer material and including a layer elastic modulus value, a layer ultimate elongation value, a layer coefficient of thermal expansion value and a layer strength value, wherein the intermediate layer is at least partially disposed between the three-dimensional multi-layered photovoltaic cell assembly and the body portion.
 9. The photovoltaic device according to claim 1, wherein the body portion is around at least a portion of the peripheral edge of the multi-layered photovoltaic cell assembly and a bottom of the three-dimensional multi-layered photovoltaic cell assembly is a bottom of the photovoltaic device at the three-dimensional multi-layered photovoltaic cell assembly.
 10. The photovoltaic device according to claim 1, wherein the localized thinning of the main body portion has a width that is about 2.5 mm to 12.5 mm.
 11. The photovoltaic device according to claim 10, wherein the barrier layer includes corners with a barrier layer peripheral edge extending therebetween and the relieving feature extends along at least about 50 percent of the barrier layer peripheral edge between the corners.
 12. The photovoltaic device according to claim 11, wherein the relieving feature is located along at least about 90 percent of the barrier layer peripheral edge between the corners.
 13. The photovoltaic device according to claim 10, wherein the relieving feature directly abuts the connector housing.
 14. The photovoltaic device according to claim 10, wherein the body portion is around at least a portion of the peripheral edge of the multi-layered photovoltaic cell assembly and a bottom of the three-dimensional multi-layered photovoltaic cell assembly is a bottom of the photovoltaic device at the three-dimensional multi-layered photovoltaic cell assembly. 